Well, here is a first preliminary test.
Canon DR (300D) Aperture priority @ f11
Artificial daylight @ ~D55
B+W Linear polarizer
Battery happened to be completely charged prior to this test, but earlier tests with depleted battery showed no significant differences.
Following image shows the cccard with 3 exposures:
1. Incorrectly polarized, camera recommended exposure (2s)
2. Incorrectly polarized, recommended exp + 1stop (4s)
3. Correctly polarized, camera recommended exposure (4s)
Incorrect polarization = correct pol + 90degr rotation
For incorrect polarization, +1stop results in the tiniest over-saturation, compensated for in ACR by -0.10 exposure correction.
For correct polarization, camera recommended exposure results happened to be perfect ETTR for sRGB.
Clearly, the correctly polarized result is more saturated and has more contrast.
Following image compares the blue patch of the +1stop incorrectly polarized image vs the correctly polarized image @ 200% magnification.
Given the significant difference that polarization makes in color rendition, even in this situation, but a complete lack of noise differences, I strongly suspect that I can not reproduce the artifacts with my equipment. It might be of course that a (B+W) linear polarizer has a completely different interaction than a circular polarizer, or something is significantly different in outside conditions.
RAW files:Correctly PolarizedIncorrectly PolarizedIncorrectly Polarized (+1stop)